Microfracture apparatuses and methods

ABSTRACT

Embodiments of apparatuses and methods for microfracture (e.g., forming a plurality of microfractures in a bone to encourage cartilage regeneration).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application Nos. 61/609,053, filed Mar. 9, 2012; 61/665,084, filed Jun. 27, 2012; 61/720,778, filed Oct. 31, 2012; 61/736,913, filed Dec. 13, 2012; and 61/755,783, filed Jan. 23, 2013; all five of which are incorporated by reference in their entireties.

BACKGROUND

1. Field of the Invention

The present invention relates generally to orthopedic treatments, more particularly, but not by way of limitation, to devices and methods for creating microfractures (e.g., in subchondral bone).

2. Description of Related Art

Examples of treatment methods and apparatuses for creating microfractures in bone are disclosed in (1) J. P. Benthien, et al., The treatment of chondral and osteochondral defects of the knee with autologous matrix-induced chondrogenesis (AMIC): method description and recent developments, Knee Surg Sports Traumatol Arthrosc, August 2011, 19(8):1316-1319; (2) Thomas J. Gill, MD, et al., The Treatment of Articular Cartilage Defects Using the Microfracture Technique, Journal of Orthopaedic & Sports Physical Therapy, October 2006, 36(10):728-738; (3) L. de Girolamo, Treatment of chondral defects of the knee with one step matrix-assisted technique enhanced by autologous concentrated bone marrow: In vitro characterisation of mesenchymal stem cells from iliac crest and subchondral bone, Injury, Int. J. Care Injured 41 (2010) 1172-1177; (4) Pub. No. US 2009/0143782; (5) Pub. No. US 2005/0043738; (6) Pub. No. US 2005/0021067; and (7) Pub. No. US 2004/0147932.

SUMMARY

This disclosure includes embodiments of apparatuses, kits, and methods for creating microfractures in bone (e.g., subchondral bone). At least some of the present embodiments are configured to create a microfracture with a greater depth-to-width ratio than has been possible with known methods and apparatuses. For example, some embodiments are configured to create a microfracture in subchondral bone having a (e.g., first) transverse dimension (e.g., diameter) of less than 1.2 millimeters (mm) (e.g., between 1 mm and 1.1 mm, less than 1.1 mm, less than 1.05 mm, less than 1 mm), and a depth (or length) of at least 5 mm (e.g., 7 mm, 8 mm, 8-10 mm, or the like).

Some embodiments of the present apparatuses comprise: a cannula having a first end, a second end, and a channel extending between the first end and the second end, the cannula having a primary portion and a distal portion between the primary portion and the second end, the distal portion configured such that a second end of the channel is disposed at an angle relative to a first end of the channel (e.g., with the distal portion disposed at an angle relative to the primary portion); and a penetrator having an enlarged head, a pointed distal end, and a (e.g., first) transverse dimension of less than 1.2 millimeters (mm) (e.g., between 1 mm and 1.1 mm, less than 1.1 mm, less than 1.05 mm, less than 1 mm), the penetrator configured to be disposed in the channel of the cannula such that the penetrator is movable between a retracted position and an extended position in which the distal end extends beyond the second end of the cannula by a penetration distance of at least 5 mm that is limited by the enlarged head contacting the cannula; where the penetrator is configured to be moved from the retracted position to the extended position substantially without rotation of the penetrator to form in subchondral bone a microfracture having a depth of at least 5 mm. In some embodiments, the penetrator comprises an elongated body and an enlarged head coupled to the elongated body. In some embodiments, the enlarged head is unitary with the elongated body.

Some embodiments of the present apparatuses comprise: a cannula having a first end, a second end, and a channel extending between the first end and the second end; and a penetrator having a distal end and a (e.g., first) transverse dimension of less than 1.2 millimeters (mm) (e.g., between 1 mm and 1.1 mm, less than 1.1 mm, less than 1.05 mm, less than 1 mm), the penetrator configured to be disposed in the channel of the cannula such that the penetrator is movable between a retracted position and an extended position in which the distal end extends beyond the second end of the cannula by a penetration distance of at least 5 mm; where the penetrator is configured to be moved from the retracted position to the extended position substantially without rotation of the penetrator to form in subchondral bone a microfracture having a depth of at least 5 mm.

Some embodiments of the present apparatuses comprise: a cannula having a first end, a second end, and a channel extending between the first end and the second end; and a penetrator having a distal end and a transverse dimension, the penetrator configured to be disposed in the channel of the cannula such that the penetrator is movable between a retracted position and an extended position in which the distal end extends beyond the second end of the cannula by a penetration distance that is at least 5 times greater than the transverse dimension of the penetrator; where the penetrator is configured to be moved from the retracted position to the extended position substantially without rotation of the penetrator to form in subchondral bone a microfracture having a depth that is at least 5 times greater than the transverse dimension of the penetrator. In some embodiments, the transverse dimension of the penetrator is less than 1.2 millimeters (mm) (e.g., between 1 mm and 1.1 mm, less than 1.1 mm, less than 1.05 mm, less than 1 mm).

In some embodiments, the cannula has a primary portion and a distal portion between the primary portion and the second end, the distal portion configured such that a second end of the channel is disposed at an angle relative to a first end of the channel. In some embodiments, the transverse dimension of the penetrator is less than 1.1 millimeters (mm). In some embodiments of the present apparatuses, the penetrator is configured to be manually moved from the retracted position to the extended position. In some embodiments, the penetrator has an enlarged head, and the penetration distance is limited by the enlarged head contacting the cannula. In some embodiments, the penetrator comprises an elongated body and an enlarged head coupled to the elongated body. In some embodiments, the enlarged head is unitary with the elongated body. In some embodiments, the cannula includes a recessed portion and a shelf, the recessed portion extending from the first end of the cannula toward the second end of the cannula, the shelf disposed between the recessed portion and the second end of the cannula such that the penetration distance is limited by the enlarged head contacting the shelf. In some embodiments, the recessed portion has a depth that is at least as large as the penetration distance. In some embodiments, the enlarged head has a cylindrical shape with a length and a transverse dimension that is smaller than the length. In some embodiments, the enlarged head has a transverse dimension that is at least 90% of a corresponding transverse dimension of the recessed portion. In some embodiments, the distal end of the penetrator is pointed. In some embodiments, the penetrator comprises at least one of a biocompatible metal, nickel-titanium alloy, stainless steel, and 316L stainless steel. In some embodiments, a coating is disposed on at least the penetration portion of the penetrator. In some embodiments, the coating is hydrophilic. In some embodiments, the coating comprises silver ions. In some embodiments, the penetrator includes a primary portion and a penetration portion, the primary portion having a circular cross-section, the penetration portion disposed between the primary portion and the distal end, the penetration portion having a circular cross-section that is smaller than the circular cross-section of the primary portion.

In some embodiments of the present apparatuses, the first transverse dimension is in the penetration portion, and a second transverse dimension smaller than the first dimension is between the first transverse dimension and the primary portion. In some embodiments, the penetration portion has a length and the second transverse dimension is substantially constant along part of the length of the penetration portion. In some embodiments, the penetration portion includes a narrow portion with at least one transverse dimension that is less than an adjacent transverse dimension of the penetration portion, such that the narrow portion is configured to reduce contact between the penetrator and a bone if the penetration portion is inserted into bone.

In some embodiments of the present apparatuses, the penetrator includes a primary portion and a penetration portion disposed between the primary portion and the distal end, the first transverse dimension is in the penetration portion, and a second transverse dimension is between the first transverse dimension and the primary portion. In some embodiments, the second transverse dimension is smaller than the first transverse dimension. In some embodiments, the penetration portion has a length, and the second transverse dimension is substantially constant along part of the length of the penetration portion. In some embodiments, the first transverse dimension is closer to the distal end than to the primary portion. In some embodiments, the penetrator has a first cross-sectional area at the first transverse dimension, the penetrator has a second cross-sectional area at the second transverse dimension, and the first cross-sectional area is larger than the second cross-sectional area. In some embodiments, the penetrator has a first circular cross section at the first transverse dimension, and the penetrator has a second circular cross section at the second transverse dimension.

In some embodiments of the present apparatuses, the distal end includes a pointed tip with a cross-sectional shape defined by a tip angle of 60 degrees or greater. In some embodiments, the tip angle is bisected by a central longitudinal axis of the penetration portion. In some embodiments, the tip angle is greater than 90 degrees. In some embodiments, the tip angle is greater than 120 degrees (e.g., 180 degrees, such that the tip is flat or at a right-angle to the longitudinal axis of the end of the penetration portion rather than pointed). In other embodiments, the tip can be rounded. Some embodiments further comprise: a penetrator removal tab coupled to the penetrator and configured to retract the penetrator relative to the cannula. In some embodiments, the cannula includes a handle, the penetrator includes a flange, the penetrator removal tab includes an opening that is has at least one transverse dimension that is smaller than a transverse dimension of the flange; and the penetrator removal tab is configured to be disposed between the handle and the flange with the penetrator extending through the opening. In some embodiments, the penetrator removal tab includes a protrusion configured to extend toward the second end of the cannula and contact the handle to act as a fulcrum for pivoting the penetrator removal tab. In some embodiments, the cannula comprises a handle having an indicator indicative of the position of the distal portion of the cannula.

Some embodiments of the present kits comprise: any embodiment of the present apparatuses, where the penetrator is a first penetrator; and a second penetrator having a distal end and a transverse dimension of less than 1.2 millimeters (mm) (e.g., between 1 mm and 1.1 mm, less than 1.1 mm, less than 1.05 mm, less than 1 mm), the second penetrator configured to be disposed in the channel of the cannula such that the second penetrator is movable between a retracted position and an extended position in which the distal end of the second penetrator extends beyond the second end of the cannula by a second penetrator penetration distance that is at least 5 mm and different than the penetration distance of the first penetrator.

Some embodiments of the present kits comprise: a first penetrator having a distal end and a transverse dimension of less than 1.2 millimeters (mm) (e.g., between 1 mm and 1.1 mm, less than 1.1 mm, less than 1.05 mm, less than 1 mm), the first penetrator configured to be disposed in a channel of a cannula such that the first penetrator is movable between a retracted position and an extended position in which the distal end extends beyond the second end of the cannula by a first penetration distance of at least 5 mm; and a package within which the penetrator is sealed. Some embodiments further comprise: a second penetrator sealed in the package, the second penetrator having a distal end and a transverse dimension, the second penetrator configured to be disposed in the channel of the cannula such that the second penetrator is movable between a retracted position and an extended position in which the distal end extends beyond the second end of the cannula by a second penetration distance; where at least one of: (i) the transverse dimension of the second penetrator is different than the transverse dimension of the first penetrator; and (ii) the second penetration distance is different than the first penetration distance. Some embodiments further comprise: a cannula having a first end, a second end, and a channel extending between the first end and the second end, the channel configured to receive the first penetrator. Some embodiments further comprise: a (e.g., reusable) tray within which the cannula is disposed.

Some embodiments of the present kits comprise: a cannula having a first end, a second end, and a channel extending between the first end and the second end, the cannula having a primary portion and a distal portion between the primary portion and the second end, the distal portion disposed at an angle relative to the primary portion, the cannula comprising metal; a re-usable, sterilizable tray; and a package within which the cannula and tray are sealed.

Some embodiments of the present methods (e.g., of forming a microfracture in subchondral bone of a patient) comprise: disposing a microfracture apparatus adjacent to the subchondral bone (the microfracture apparatus comprising: a cannula having a first end, a second end, and a channel extending between the first end and the second end; and a penetrator having a distal end and a transverse dimension of less than 1.2 millimeter (mm) (e.g., between 1 mm and 1.1 mm, less than 1.1 mm, less than 1.05 mm, less than 1 mm)); and advancing the penetrator relative to the cannula, substantially without rotation of the penetrator, until the distal end of the penetrator extends into the subchondral bone to form a microfracture having a depth greater than 5 mm. Some embodiments further comprise: repeating the steps of disposing and advancing to form a plurality of microfractures in the subchondral bone. In some embodiments, the apparatus further comprises a penetrator removal tab coupled to the penetrator and configured to retract the penetrator relative to the cannula, and the method further comprises: actuating the penetrator removal tab to retract the distal end of the penetrator from the bone. In some embodiments, the cannula includes a handle, the penetrator includes a flange, the penetrator removal tab includes an opening that is has at least one transverse dimension that is smaller than a transverse dimension of the flange; and the penetrator removal tab is configured to be disposed between the handle and the flange with the penetrator extending through the opening. In some embodiments, the penetrator removal tab includes a protrusion configured to extend toward the second end of the cannula and contact the handle to act as a fulcrum for pivoting the penetrator removal tab, and actuating the penetrator removal tab includes pivoting the penetrator removal tab around a point of contact between the protrusion and the handle. In some embodiments, the cannula comprises a handle having an indicator indicative of the position of the distal portion of the cannula.

In some embodiments, the microfracture apparatus is disposed such that the second end of the cannula contacts the subchondral bone.

In some embodiments of the present methods, the penetrator is advanced manually. In some embodiments, the position of the second end of the cannula relative to the bone is substantially constant while advancing the penetrator. In some embodiments, the penetrator has an enlarged head, and the penetration distance is limited by the enlarged head contacting the cannula. In some embodiments, the cannula includes a recessed portion and a shelf, the recessed portion extending from the first end of the cannula toward the second end of the cannula, the shelf disposed between the recessed portion and the second end of the cannula such that the penetration distance is limited by the enlarged head contacting the shelf. In some embodiments, the recessed portion has a depth that is at least as large as the penetration distance. In some embodiments, the enlarged head has a cylindrical shape with a length and a transverse dimension that is smaller than the length. In some embodiments, the enlarged head has a transverse dimension that is at least 90% of a corresponding transverse dimension of the recessed portion. In some embodiments, the distal end of the penetrator is pointed. In some embodiments, the penetrator includes a primary portion and a penetration portion, the primary portion having a circular cross-section, the penetration portion disposed between the primary portion and the distal end, the penetration portion having a circular cross-section that is smaller than the circular cross-section of the primary portion.

Any embodiment of any of the present apparatuses and methods can consist of or consist essentially of—rather than comprise/include/contain/have—any of the described steps, elements, and/or features. Thus, in any of the claims, the term “consisting of” or “consisting essentially of” can be substituted for any of the open-ended linking verbs recited above, in order to change the scope of a given claim from what it would otherwise be using the open-ended linking verb.

Details associated with the embodiments described above and others are presented below.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings illustrate by way of example and not limitation. For the sake of brevity and clarity, every feature of a given structure is not always labeled in every figure in which that structure appears. Identical reference numbers do not necessarily indicate an identical structure. Rather, the same reference number may be used to indicate a similar feature or a feature with similar functionality, as may non-identical reference numbers. The figures are drawn to scale (unless otherwise noted), meaning the sizes of the depicted elements are accurate relative to each other for at least the embodiment depicted in the figures.

FIG. 1A depicts a perspective view of a first embodiment of the present apparatuses having a cannula and a penetrator, with the cannula shown next to the penetrator.

FIG. 1B depicts a cross-sectional view of the apparatus of FIG. 1A, with the cannula shown next to the penetrator.

FIG. 1C depicts a cross-sectional view of an enlarged head of the penetrator shown in FIG. 1A.

FIG. 1D depicts a cross-sectional view of a first end of the cannula shown in FIG. 1A.

FIG. 2A depicts a perspective view of the apparatus of FIG. 1A, with the penetrator shown in the cannula.

FIG. 2B depicts a cross-sectional view of the apparatus of FIG. 1A, with the penetrator shown in the cannula.

FIG. 2C depicts a cross-sectional view of a portion of the apparatus of FIG. 1A that includes a second end of the cannula and a distal end of the penetrator, with the penetrator shown in the cannula.

FIG. 3 depicts a perspective view of a second embodiment of the present apparatuses.

FIGS. 4A and 4B depict perspective view of the apparatus of FIG. 3 positioned for use relative to a patient's knee, and are not drawn to scale.

FIG. 5A depicts a side view of a second embodiment of the present penetrators.

FIGS. 5B and 5C depict enlarged side views of a penetration portion of the penetrator of the penetrator of FIG. 5A.

FIG. 6 depicts a side cross-sectional view of a second embodiment of the present cannulas.

FIG. 7A depicts a side cross-sectional view of a third embodiment of the present cannulas.

FIG. 7B depicts an enlarged cross-sectional view of a distal portion of the cannula of FIG. 7A.

FIGS. 8A-8C depict various views of handle for use with the present cannulas.

FIG. 9 depicts an exploded perspective view of a kit comprising an embodiment of the present apparatuses and a package for the apparatus.

FIGS. 10A-10D depict various views of another embodiment of the present apparatuses that includes a penetrator removal tab in combination with the penetrator of FIG. 5A and a fourth embodiment of the present cannulas.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The term “coupled” is defined as connected, although not necessarily directly, and not necessarily mechanically; two items that are “coupled” may be unitary with each other. The terms “a” and “an” are defined as one or more unless this disclosure explicitly requires otherwise. The term “substantially” is defined as largely but not necessarily wholly what is specified (and includes what is specified; e.g., substantially 90 degrees includes 90 degrees and substantially parallel includes parallel), as understood by a person of ordinary skill in the art. In any embodiment of the present apparatuses, kits, and methods, the term “substantially” may be substituted with “within [a percentage] of” what is specified, where the percentage includes 0.1, 1, 5, and/or 10 percent.

The terms “comprise” (and any form of comprise, such as “comprises” and “comprising”), “have” (and any form of have, such as “has” and “having”), “include” (and any form of include, such as “includes” and “including”) and “contain” (and any form of contain, such as “contains” and “containing”) are open-ended linking verbs. As a result, an apparatus or kit that “comprises,” “has,” “includes” or “contains” one or more elements possesses those one or more elements, but is not limited to possessing only those elements. Likewise, a method that “comprises,” “has,” “includes” or “contains” one or more steps possesses those one or more steps, but is not limited to possessing only those one or more steps.

Further, an apparatus, device or system that is configured in a certain way is configured in at least that way, but it can also be configured in other ways than those specifically described.

Referring now to the drawings, and more particularly to FIGS. 1A-2C, shown therein and designed by the reference numeral 10 is one embodiment of the present apparatuses for creating microfractures in bone (e.g., subchondral bone). In the embodiment shown, apparatus 10 comprises a penetrator 14, a cannula 18, and a handle 22 coupled to cannula 18. In other embodiments (e.g., as shown in FIG. 3), handle 22 may be omitted. In the embodiment shown, cannula 18 has a first end 26, a second end 30, and a channel 34 extending between the first end and the second end. Such first and second ends should be understood as the locations of the beginning and end of the channel. In this embodiment, cannula 18 has a primary portion 38 and a distal portion 42, with primary portion 38 extending between first end 26 and distal portion 42 (e.g., a majority of the length of the cannula, as in the embodiment shown), and with distal portion 42 extending between primary portion 38 and second end 30. The distal portion can be configured such that a second end of the channel (at second end 30) is disposed at an angle relative to a first end of the channel (at first end 26). For example, in the embodiment shown, distal portion 42 is disposed at an angle 46 relative to the primary portion. In the embodiment shown, angle 46 is between 10 and 30 degrees (e.g., 20 degrees). In other embodiments, angle 46 can be any size that permits apparatus 10 to function as described in this disclosure (e.g., angle 46 can be equal to, or between any two of: 0, 10, 20, 30, 40, 45, 50, and/or 60 degrees). In other embodiments, angle 46 can be greater than 60 degrees (e.g., equal to, or between any two of: 60, 70, 80, 90, and/or more degrees). As a further example, distal portion 42 can include a curved or hooked shape such that angle 46 is effectively larger than 90 degrees (e.g., equal to, or between any two of: 90, 120, 150, 180, and/or 180 degrees).

Primary portion 38 has a transverse dimension 50 (e.g., a diameter, in the embodiment shown). Penetrator 14 and cannula 18 can comprise any suitable material that permits the apparatus to function as described in this disclosure (e.g., and permits the penetrator and the cannula to be sterilized). For example, in some embodiments, penetrator 14 comprises nickel-titanium alloy (e.g., Nitinol), and/or cannula 18 comprises metal, such as stainless steel (e.g., a surgical stainless steel). Embodiments of the present cannulas are rigid and configured not to flex or bend during use. In other embodiments, penetrator 14 can comprise a biocompatible metal such as stainless steel (e.g., 316L stainless steel).

In the embodiment shown, penetrator 14 has a proximal end 54, an enlarged head 58 adjacent proximal end 54, a primary portion 62, a distal end 66 (e.g., pointed distal end 66, as shown), and a penetration portion 70 adjacent distal end 66. In this embodiment, penetration portion 70 has a length 74 that is a minority of the length of penetrator 14 between proximal end 54 and distal end 66. In some embodiments, penetrator 14 has a transverse dimension of less than 1.2 mm (e.g., between 1 mm and 1.1 mm; less than 1.1 mm, less than 1.05 mm, less than 1 mm; less than, or between any two of, 0.5, 0.6, 0.7, 0.8, 0.9, and/or 1 mm). For example, in the embodiment shown, penetration portion 70 has a circular cross-section with a diameter 78 of between 0.7 and 0.8 mm (e.g., 0.78 mm). In some embodiments, penetration portion 70 has a circular cross-section with a diameter of between 1 and 1.1 mm (e.g., 1.04 mm). Penetrator 14 is configured to be disposed in channel 34 of cannula 18 such that penetrator 14 is movable between a (1) retracted position (e.g., in which distal end 66 of the penetrator does not extend beyond second end 30 of the cannula) and (2) an extended position in which distal end 66 of the penetrator extends beyond second end 30 of the cannula by a penetration distance 82. In some embodiments, penetration distance 82 is at least (e.g., greater than) 5 mm (e.g., 7 mm, 8 mm, 8-10 mm, more than 10 mm) and/or at least (e.g., greater than) 5 times (e.g., greater than, or between any two of: 6, 7, 8, 9, 10, or more times) a transverse dimension (e.g., diameter) of penetrator 14 (e.g., diameter 78 of penetration portion 70). For example, in the embodiment shown, penetration distance 82 is between 8 mm and 10 mm (e.g., 10 mm), which is greater than 12 times diameter 78. In the embodiment shown, diameter 50 of primary portion 38 is larger than diameter 78 of penetration portion 70. In some embodiments, diameter 50 is also less than 1.2 mm (e.g., between 1 mm and 1.1 mm, less than 1.1 mm, less than 1.05 mm). In some embodiments, diameter 50 is substantially equal to diameter 78. In some embodiments, penetrator 14 comprises a central wire defining diameter 78 that is encircled or encased by an outer tubing (e.g., metallic tubing, plastic shrink wrap, and/or the like along the length of primary portion 62 to define transverse dimension 50.

In some embodiments, a coating is disposed on at least penetration portion 70 of penetrator 14 (the coating may also be disposed on primary portion 62 of the penetrator). In some embodiments, the coating is hydrophilic. Examples of hydrophilic coatings include Hydro-Silk coatings available from TUA Systems of Florida (U.S.A.). In some embodiments, the coating comprises silver ions. In some embodiments, the coating comprises one or more active ingredients configured to elicit or stimulate a biological response in (e.g., bone or cartilage) tissue, such as, for example, growth factor(s), anticoagulant(s), protein(s), and/or the like. Such coatings can be applied as known in the art for the materials used in particular embodiments.

In the embodiment shown, cannula 18 is configured to provide lateral support for penetrator 14, such as to prevent the penetrator from bending or buckling while being driven into the hard subchondral bone. For example, in the embodiment shown, diameter 50 of primary portion 62 of the penetrator is nearly as large as (e.g., greater than, or between any two of: 95, 96, 97, 98, 99, and or 100 percent of) the diameter of channel 34, and diameter 78 of penetration portion 70 is greater than 75% (e.g., greater than, or between any two of: 75, 80, 85, 90, 95, and/or 100 percent of) the diameter of channel 34 (e.g., the diameter of channel 34 adjacent second end 30 of the cannula). In some embodiments, penetrator 14 is substantially straight prior to being disposed in channel 34 of cannula 18, such that inserting the penetrator into the cannula causes the penetration portion 70 of the penetrator to be angled relative to primary portion 62. In some such embodiments, penetrator 14 may be resilient enough to (e.g., at least partially) return to its straight shape after removal from the cannula.

In some embodiments, penetrator 14 is configured to be moved or advanced (e.g., substantially without rotation of the penetrator) from the retracted position to the extended position (FIG. 2B) to form a microfracture in subchondral bone (e.g., in a patient's knee or shoulder joint), the microfracture having a depth of at least (e.g., more than) 5 mm (e.g., 7 mm, 8 mm, 8-10 mm, more than 10 mm) and/or at least (e.g., greater than) 5 times (e.g., greater than, or between any two of: 6, 7, 8, 9, 10, or more times) a transverse dimension (e.g., diameter) of penetrator 14 (e.g., diameter 78 of penetration portion 70). For example, in the embodiment shown, penetrator 14 is configured to be moved or advanced (e.g., substantially without rotation of the penetrator, which includes no rotation up to rotation of less than one full revolution clockwise and/or counterclockwise from the position at which distal end 66 of the penetrator first contacts the bone) from the retracted position to the extended position (FIG. 2B) to form a microfracture in subchondral bone (e.g., in a patient's knee or shoulder joint), the microfracture having a depth of between 8 mm and 10 mm (e.g., 10 mm), which is greater than 12 times diameter 78. In the embodiment shown, penetrator 14 is configured to be moved or advanced manually to the extended position. As used in this disclosure, moved or advanced “manually” means without the assistance of an external energy source other than that provided by a user. For example, if the penetrator is moved or advanced with a battery-powered or spring-driven driver, it would not be “manually.” Conversely, the penetrator would be moved or advanced “manually” if a mallet, hammer, or other tool is swung by a user (e.g., in the user's hand) to impact first end 26 of the penetrator. In some embodiments, the present apparatuses are configured such that the penetrator can (but need not) be rotated as it is advanced or moved from the retracted position to the advanced position. For example, a portion of the penetrator (e.g., enlarged head 58) can be disposed in the chuck of a drill such that the drill can rotate the penetrator. In such embodiments, the penetrator may (but need not) be substantially straight or axial (without bends) along its entire length (e.g., prior to being disposed in a cannula with an angled distal portion).

In the embodiment shown, penetration distance 82 (and the depth of the microfracture the apparatus is configured to create) is limited by enlarged head 58 contacting the cannula (e.g., penetration distance is maximized when enlarged head 58 contacts the cannula, as shown in FIG. 2B). For example, in the embodiment shown, cannula 18 includes a recessed portion 86 and a shelf 90. As shown, recessed portion 86 extends from first end 26 toward second end 30 (inwardly), and shelf 90 is disposed between recessed portion 86 and second end 30 such that penetration distance 82 is limited by enlarged head 58 contacting shelf 90. For example, in the embodiment shown, enlarged head 58 has a cylindrical (e.g., circular cylindrical, as shown) with a first end 94 and a second end 98, and is configured such that second end 98 contacts shelf 90 when the penetrator is in the extended position relative to the cannula (FIG. 2B). In some embodiments, recessed portion 86 can be configured to maintain the orientation or alignment of enlarged head 58 as the penetrator is moved or advanced from the retracted position to the extended position. For example, in some embodiments, recessed portion 58 has a depth 102 that is at least as large as (e.g., is greater than, or between any two of: 100, 110, 120, 130, 140, 150, or more percent of) penetration distance 82 (e.g., such that enlarged head 58 is at least partially within recessed portion 86 when distal end 66 extends beyond second end 30 of the cannula), and/or enlarged head 58 has a transverse dimension (e.g., diameter) that is at least 90% (e.g., greater than, or between any two of: 90, 92, 94, 96, 98, and/or 100 percent) of a corresponding transverse dimension of recessed portion 86 (e.g., such that cannula 18 limits tilting of enlarged head 58 relative to cannula 14, and/or limits misalignment of enlarged head 58 relative to primary portion 62 of the penetrator).

For example, in the embodiment shown, depth 102 of recessed portion 58 is between 175% and 250% (e.g., between 200% and 225%) of penetration distance 82. In this embodiment, enlarged head 58 and recessed portion 86 each has a circular cross section, and enlarged head 58 has a diameter 106 that is between 90% and 100% (e.g., between 95% and 100%) of diameter 110 of recessed portion 86. In some embodiments, a length 114 of enlarged head 58 is at least 150% (e.g., at least, or between any two of: 150, 175, 200, 225, 250, 300, or more percent) of penetration distance 82. For example, in the embodiment shown, length 114 is over 300% of penetration distance 82, such that a portion of enlarged head 58 that is at least as long as penetration distance 82 is disposed in recessed portion 86 when distal end 66 of the penetrator is even with second end 30 of the cannula (and the orientation of enlarged head 58 relative to cannula 18 is thereby maintained). In some embodiments, enlarged head 58 has an elongated shape such that length 114 is greater than (e.g., greater than, or between any two of: 2, 3, 4, 6, 8, or more times) diameter 106. For example, in the embodiment shown, length 114 is between 8 and 12 times diameter 106.

FIG. 3 depicts a second embodiment 10 a of the present apparatuses. Apparatus 10 a is substantially similar to apparatus 10, with the exception that apparatus 10 a does not include a handle (e.g., handle 22).

Embodiments of the present kits can comprise one or more of the present cannulas (e.g., cannula 14) and a reusable tray or other container in a package (e.g., a sealed pouch or the like), where both the cannula(s) and the tray are or can be sterilized (and can be re-sterilized in advance of being re-used). Both the tray and the package may be rectangular in shape. In addition, some embodiments of the present kits can also include two or more penetrators configured to create different microfractures. For example, some embodiments of the present kits comprise one or more of the present cannulas, a sterlizable tray, a first penetrator configured to have a penetration distance of between 5 mm and 8 mm when used in combination with the cannula, and a second penetrator configured to have a penetration distance greater than 8 mm when used in combination with the cannula. More specifically, some embodiments of the present kits may include a package (e.g., a box or a flexible package) that comprises sterilized versions of these items. Other embodiments of the present kits comprise one or more of the present penetrators (e.g., a single penetrator or two penetrators having different penetration depths, different tip diameters, different tip shapes, and/or the like) that are sterile and disposed in a package. Embodiments of the present kits may also include, in more specific embodiments, instructions for use, which instructions may be inside the package (e.g., as an insert) or outside the package (such as a sticker on the package).

FIGS. 4A and 4B depict an example of the present methods (e.g., using embodiment 10 a of the present apparatuses). Some embodiments of the present methods comprise: disposing an embodiment of the present microfracture apparatuses (e.g., 10, 10 a) adjacent to subchondral bone of a patient (e.g., in the knee, shoulder, or other joint). For example, in the embodiment shown, apparatus 10 a is disposed adjacent to subchondral bone of articular surface 150 in a patient's knee 154 (e.g., with second end 30 of cannula 18 in contact with the subchondral bone, as shown). Some embodiments further comprise moving or advancing penetrator 14 relative to cannula 18 (e.g., from FIG. 4A to FIG. 4B) until distal end 66 of the penetrator extends into the subchondral bone (as in FIG. 4B) to form a microfracture having a depth of at least 5 mm. For example, in the embodiment shown, penetrator 18 is manually advanced substantially without rotation of the penetrator by striking or impacting proximal end 54 of the penetrator with a mallet 158 until distal end 66 extends into the subchondral bone by a distance of, and forms a microfracture 162 having a depth of, 10 mm. In the embodiment shown, the position of second end 30 of the cannula relative to the subchondral bone remains substantially constant while advancing the penetrator into the bone. In some embodiments of the present methods, the apparatus is repeatedly disposed adjacent the bone (e.g., with second end 30 of the cannula in contact with the subchondral bone and/or in contact with cartilage, such as, for example, cartilage around the perimeter of a lesion), and the penetrator is repeatedly advanced into the subchondral bone to form a plurality of microfractures (e.g., having substantially the same depths). In some embodiments, the present methods can be performed on and/or in the surfaces of other joints, such as, for example, the shoulder, the ankle, the hip, and/or the patellofemoral joint within the knee.

Referring now to FIGS. 5A-5C, a second embodiment 14 a of the present penetrators is shown. Penetrator 14 a is similar in many respects to penetrator 14. For example, penetrator 14 a has a proximal end 54, a primary portion 62, a distal end 66 (e.g., pointed distal end 66, as shown), and a penetration portion 70 a adjacent distal end 66. While not shown in FIG. 5A, penetrator 14 a can also include an enlarged head (similar to enlarged head 58 of penetrator 14). In this embodiment, penetration portion 70 a has a length 74 a that is a minority of the length of penetrator 14 a between proximal end 54 and distal end 66. Similarly, in some embodiments, penetrator 14 a has a transverse dimension of less than 1.2 mm (e.g., between 1 mm and 1.1 mm; less than 1.1 mm, less than 1.05 mm, less than 1 mm; less than, or between any two of, 0.5, 0.6, 0.7, 0.8, 0.9, and/or 1 mm). For example, in the embodiment shown, penetration portion 70 a has a circular cross-section with a diameter 78 a of between 1 and 1.2 mm (e.g., 1.04 mm). As with penetrator 14, penetrator 14 a is configured to be disposed in channel 34 of cannula 18 such that penetrator 14 is movable between a (1) retracted position (e.g., in which distal end 66 of the penetrator does not extend beyond second end 30 of the cannula) and (2) an extended position in which distal end 66 of the penetrator extends beyond second end 30 of the cannula by a penetration distance 82, which may, for example, be at least (e.g., greater than) 5 mm (e.g., 7 mm, 8 mm, 8-10 mm, more than 10 mm) and/or at least (e.g., greater than) 5 times (e.g., greater than, or between any two of: 6, 7, 8, 9, 10, or more times) a transverse dimension (e.g., diameter) of penetrator 14 (e.g., diameter 78 a of penetration portion 70).

For example, in the embodiment shown, penetration distance 82 is between 8 mm and 10 mm (e.g., 10 mm), which is greater than 7 times diameter 78 a. In some embodiments, the length of the penetration portion is greater than a penetration distance 82 for which the penetrator is designed. For example, in the embodiment shown, length 74 a is greater than the penetration distance 82 (e.g., and greater than the sum of penetration distance 82 and the length of distal portion 42 of cannula 14 and/or cannula 14 a). In the embodiment shown, diameter 50 of primary portion 38 is larger than diameter 78 a of penetration portion 70 a, and/or equal to or greater than 1.2 mm (e.g., substantially equal to 1.27 mm) and/or less than 2.0 mm. In some embodiments, diameter 50 is also less than 1.2 mm (e.g., between 1 mm and 1.1 mm, less than 1.1 mm, less than 1.05 mm). In some embodiments, diameter 50 is substantially equal to diameter 78.

In some embodiments, penetrator 14 comprises a central wire defining transverse dimension 78 a that is encircled or encased by an outer tubing (e.g., metallic tubing, plastic shrink wrap, and/or the like along the length of primary portion 62 a to define transverse dimension 50 a.

As shown in FIGS. 5B and 5C, however, penetration portion 70 a differs from penetration portion 70 in that penetration portion 70 a is configured to reduce (e.g., relative to that of penetration portion 70) the force required to insert distal end 66 into a bone, and to reduce (e.g., relative to that of penetration portion 70) the force required to remove distal end 66 from the bone. For example, in the embodiment shown, penetration portion 70 includes a narrow portion 200 between distal end 66 and primary portion 62, with narrow portion 200 being narrower in at least one transverse dimension than primary portion 62. In this embodiment, narrow portion 200 is configured to reduce the surface area of penetration portion 70 a that is in contact with bone when the penetration portion is driven into a bone. For example, the enlarged part of penetration portion 70 a adjacent distal end 66 (and corresponding to first transverse dimension 78 a) creates a path through the bone during insertion that is larger than narrow portion 200, such that at least a part of narrow portion 200 is not (at least initially) in contact with the bone. Even if penetration portion 70 a remains in the bone for a sufficient time for the bone to rebound towards narrow portion 200, the reduced transverse dimension of narrow portion 200 may reduce the interface pressure between the penetrator and the rebounded bone material. This reduced contact and/or reduced interface pressure can reduce the force required to remove distal end 66 from the bone (e.g., relative to the force required to remove from the same type of bone penetration portion 70 of penetrator 14, which has a circular cylindrical shape with constant diameter and cross-section along the length of penetration portion 70—i.e., does not include narrow portion 200).

For example, in the embodiment shown, transverse dimension 78 a is a first transverse dimension in the penetration portion, and a second transverse dimension 204 that is smaller than first transverse dimension 78 a is between primary portion 62 and first transverse dimension 78 a (in penetration portion 70 a, as shown). In some embodiments, second transverse dimension 204 is substantially constant along part of length 74. For example, in the embodiment shown, narrow portion 200 has a length 208 along which second transverse dimension 204 is substantially constant. In the embodiment shown, length 208 is between 20 percent and 35 percent of length 74 a of penetration portion 70 a. In other embodiments, length 208 can be any suitable fraction or percentage of length 74 a (e.g., less than any one of, or between any two of, 5, 10, 15, 20, 25, 30, 35, 40, 45, and/or 50 percent). In some embodiments, first transverse dimension 78 a is adjacent distal end 66 (i.e., closer to distal end 66 than to primary portion 62). For example, in the embodiment shown, the distance between distal end 66 and narrow portion 200 is less than length 208 of the narrow portion. In other embodiments, narrow portion can be disposed at any suitable position along the length of penetration portion 70 a. In the embodiment shown, penetration portion 70 a further includes a third transverse dimension 212 between narrow portion 200 and primary portion 62. In this embodiment, third transverse dimension 212 is substantially equal to first transverse dimension 78 a, but may differ in other embodiments. In the embodiment shown, third transverse dimension is substantially constant along a proximal segment 214 of penetration portion 70 a.

In some embodiments, penetrator 14 a has a first cross-sectional shape and/or area at first transverse dimension 78 a, a second cross-sectional shape and/or area at second transverse dimension 204, and the first cross-sectional shape and/or area is larger than (e.g., and, as shown, concentric to) the second cross-sectional shape and/or area. For example, in the embodiment shown, penetrator 14 a has a first circular cross section at first transverse dimension 78 a, and a second circular cross section at second transverse dimension 204 (e.g., with the first circular cross-section being substantially concentric with the second circular cross-section, as shown). In this embodiment, penetrator 14 a also has a circular cross-section at third transverse dimension 212. In other embodiments, the penetrator, the penetration portion, and/or the narrow portion can have any suitable cross-sectional shapes (e.g., circle, square, triangular, rectangular, star, and/or the like), whether similar or dissimilar (e.g., the cross-sectional shape of the narrow portion may differ from the cross-sectional shape of the remainder of the penetration portion), such that the cross-sectional shape of the surface of area of the narrow portion that contacts bone during insertion is reduced. For example, in some embodiments, the penetration portion can have a circular cross-section and the narrow portion can have a rectangular cross-section. In other embodiments, narrow portion 200 may be fluted.

In the embodiment shown, penetration portion 70 a also differs from penetration portion 70 in that distal end 66 is configured to reduce (e.g., relative to that of penetration portion 70) the force required to insert distal end 66 into a bone, and to reduce (e.g., relative to that of penetration portion 70) the force required to remove distal end 66 from the bone. For example, in the embodiment shown, distal end 66 includes a pointed tip 216 with a cross-sectional shape defined by a tip angle 220 of 60 degrees or greater (e.g., substantially equal to 60 degrees, as shown). For example, in the embodiment shown, pointed tip 216 has a conical shape having a cross-sectional shape that is bisected by a central longitudinal axis 224 of penetration portion 70 a. In other embodiments, pointed tip 216 can have any suitable shape (e.g., a triangular or rectangular pyramid). In some embodiments, tip angle 220 is greater than 60 degrees, greater than 90 degrees, and/or greater than 120 degrees (e.g., equal to 180 degrees, or substantially perpendicular to a longitudinal axis of an adjacent portion of penetration portion 70 a). For example, a tip angle 220 of 60 degrees, as shown, reduces the length of the cone that defines pointed tip relative to the 30 degree tip angle of penetrator 14, and thereby reduces the surface area of the cone that is available to contact bone during insertion and removal. Likewise, further increases in tip angle 220 will further reduce the surface area of a conical pointed that is available to contact bone. In the embodiment shown, penetration portion 70 a further includes a first radiused portion 228 (which may instead be linearly tapered) between pointed tip 216 (and first transverse dimension 78 a) and narrow portion 200, and a second tapered portion 232 (which may instead be radiused) between proximal segment 214 and narrow portion 200, to reduce likelihood of the transitions in transverse dimension resulting in points along penetration portion 70 a that might otherwise catch or resist insertion or removal of distal end 66 into or from bone. In other embodiments, the tip can be rounded and/or can be defined by a single (e.g., planar) facet extending across the entire cross-section of the penetration portion.

In the embodiment shown, penetrator 14 a is substantially straight prior to being disposed in channel 34 of cannula 18 or cannula 18 b, such that inserting the penetrator into the cannula causes the penetration portion 70 a of the penetrator to bend within channel 34 (between primary portion 38 or 38 a and distal portion 42 or 42 a). In some such embodiments, penetrator 14 a may be resilient enough to (e.g., at least partially) return to its straight shape after removal from the cannula.

FIG. 6 depicts a side cross-sectional view of a second embodiment 18 a of the present cannulas. Cannula 18 a is similar in many respects to cannula 18. For example, cannula 18 a has a first end 26, a second end 30, and a channel 34 extending between the first end and the second end. Such first and second ends should be understood as the locations of the beginning and end of the channel. In this embodiment, cannula 18 has a primary portion 38 a and a distal portion 42 a, with primary portion 38 a extending between first end 26 and distal portion 42 a (e.g., a majority of the length of the cannula, as in the embodiment shown), and with distal portion 42 a extending between primary portion 38 and second end 30. In the embodiment shown, cannula 18 a differs from cannula 18 in that in cannula 18 a, distal portion 42 a is not angled relative to primary portion 38 a (distal portion 42 a and primary portion 38 a share a common central longitudinal axis). Primary portion 38 a has a transverse dimension 300 (e.g., a diameter, in the embodiment shown). In the embodiment shown, distal portion 42 a is tapered between primary portion 38 a and second end 30, as shown. In this embodiment distal portion 42 a has a length 304 that is less than a length 308 of cannula 18 a (e.g., less than 20 percent of length 308). In other embodiments, the relative lengths of primary portion 38 a and distal portion 42 a can be any suitable sizes for various procedures and/or for patients of various ages and/or sizes. In some embodiments of the present methods, cannula 18 a is bent to form a cannula with an angled distal portion, as described below.

Referring now to FIGS. 7A and 7B, side cross-sectional views are shown of a third embodiment 18 b of the present cannulas. Cannula 18 b is substantially similar to cannula 18, with the exception that angle 46 b is substantially equal to 15 degrees. In some embodiments, angle 46 b can be between 5 degrees and 20 degrees (e.g., substantially equal to either of, or between, 10 degrees and 15 degrees). In other embodiments, angle 46 b can be greater than 60 degrees (e.g., equal to, or between any two of: 60, 70, 80, 90, and/or more degrees). As a further example, distal portion 42 b can include a curved or hooked shape such that angle 46 b is effectively larger than 90 degrees (e.g., equal to, or between any two of: 90, 120, 150, 180, and/or 180 degrees).

FIGS. 7A and 7B also include dimensions (in inches) for at least one exemplary embodiment of the present cannulas. Further, the difference between cannula 18 a of FIG. 6 and cannula 18 b of FIGS. 7A and 7B illustrate an embodiment of the present methods. In particular, some embodiments of the present methods (e.g., of making the present cannulas) comprise forming cannula 18 b by bending (e.g., with a jig or the like) cannula 18 a to angle 46.

FIGS. 8A-8C depict various views of handle 22. FIG. 8B includes dimensions (in inches) for at least one exemplary embodiment of the present handles. As shown, handle 22 comprises a central longitudinal passage 312 configured to receive part of a primary portion (e.g., 38, 38 a) of a cannula (e.g., 18, 18 a, 18 b), such as, for example, via a press fit or the like.

FIG. 9 depicts an exploded perspective view of a kit 400 comprising an embodiment 10 of the present apparatuses and a package 404 for the apparatus. In the embodiment shown, package 404 comprises a lower panel 408, a foam or other (e.g., molded plastic) receptacle 412 configured to receive apparatus 10 (including penetrator 14 and cannula 18), and an upper panel 416. In the embodiment shown, kit 400 also includes instructions 420 and a box 424. As indicated by the arrangement of panels 408 and 416, receptacle 412, and instructions 420, these components fit into box 424. In some embodiments, such as the one shown, cannula 18 (including handle 22) and/or penetrator 14 are sterile and/or sealed in plastic independently of receptacle 412.

FIGS. 10A-10D depict various views of another embodiment 10 b of the present apparatuses that includes a penetrator removal tab 500 in combination with a penetrator 14 b and a fourth embodiment 18 c of the present cannulas. In the embodiment shown, tab 500 comprises a body 504 with a first end 508, a second end 512, a distal side 516, and a proximal side 520. In the embodiment shown, distal side 516 is configured to face toward second end 30 of cannula 18 c, and comprises a protrusion 524 configured to contact handle 22 to act as a fulcrum during use, as described in more detail below. In the embodiment shown, distal side 520 includes a plurality of grooves 528 to contact and resist slippage of a user's thumb during use. In other embodiments, grooves 528 may be omitted and/or substituted with a different type of texture. As shown in FIGS. 10C and 10D, body 504 has a curved or arcuate shape such that distal side 516 is concave and proximal side 520 is convex.

In the embodiment shown, body 504 includes an elongated opening 532 that is closer to first end 508 than to second end 512, and that is configured to receive enlarged head 58 of penetrator 14 a as shown in FIGS. 10B and 10C. For example, in some embodiments, opening 516 can have a width (smaller transverse dimension) that is between 100% and 150% (e.g., between any two of: 100%, 110%, 120%, 130%, 140%, and 150%) of a corresponding transverse dimension (e.g., diameter 106) of enlarged head 58, and/or can have a height (larger transverse dimension) that is between 150% and 250% (e.g., between any two of: 150%, 175%, 200%, 225%, and 250%) of a corresponding transverse dimension (e.g., diameter 106) of enlarged head 58. The elongated shape of opening 532 permits tab 500 to pivot relative to enlarged head 58 (and overall penetrator 14 b) to apply an axial removal force to penetrator 14 b while minimizing any lateral force that might otherwise deflect and/or impede movement of the penetrator.

As shown, proximal side 520 of body 504 also includes a recess 536 configured to at least partially receive FIG. 10C) a corresponding flange 542 that is coupled to (e.g., unitary with) enlarged head 58. For example, in the embodiment shown, flange 542 is configured to be disposed over and coupled in fixed relation to proximal end 54 and enlarged head 58 of penetrator 14 b. In his embodiment, flange 542 includes a neck 546 configured to be crimped and/or adhered via adhesive to enlarged head 58. In other embodiments, flange 542 may be unitary with enlarged head. As shown, flange 542 has a transverse dimension (e.g., diameter) that is larger than a corresponding transverse dimension (e.g., diameter) of opening 504 but smaller than a corresponding transverse dimension of recess 536. In some embodiments, enlarged head 58 is omitted and flange 542 and opening 528 (e.g., and recess 532) also limits the maximum penetration distance 82.

In use, a penetrator 14 b (e.g., having flange 542 coupled to enlarged head 58) can be inserted through opening 528 and into cannula 18 c such that tab 500 is disposed between flange 542 and handle 22 a of cannula 18 c. Second end 30 of cannula 18 c can then be disposed in a desired location relative to a bone, and penetrator 14 b can be impacted to drive distal end 66 of the penetrator into the bone. With distal end 66 disposed in the bone, a user can apply a force to proximal side 520 of tab 500 in direction 550 (toward second end 30 of cannula 18 c) to cause tab 500 to pivot around protrusion 524 and apply a force to flange 542 to retract the penetrator in direction 524. In the embodiment shown, protrusion 524 is sized such that a second part of tab 500 (504) will also contact handle 22 a at point 558 (such that protrusion once the penetrator is retracted by a distance about equal to or just larger than the maximum penetration distance (e.g., 82 of FIG. 2C) of the penetrator/cannula combination to prevent protrusion 524 from further acting as a fulcrum for tab 500. For example, limiting the retraction distance (e.g., to between 100% and 120% of maximum penetration distance 82) in this way can minimize the lateral force applied to enlarged head 58 during retraction of the penetrator and can facilitate reinsertion of the penetrator in a new location by minimizing the distance the penetrator must be advanced to bring its distal end (66) into initial contact with the bone at the new location.

In the embodiment shown, handle 22 a is substantially similar to handle 22 with the exception that handle 22 a includes a protrusion 562 that is aligned with distal portion 42 of cannula 18 c. For example, in this embodiment, primary portion 38 of cannula 18 c, distal portion 42 of cannula 18 c, and protrusion 562 of handle 22 d are each bisected by a single common plane. Protrusion 562 thus provides an indicator for a user of the orientation of distal portion 42 (e.g., even when distal portion 42 is disposed within a patient and out of the user's sight). In other embodiments, any suitable indicator may be used (e.g., a depression instead of a protrusion, an arrow printed or painted on handle 22, and/or the like).

The above specification and examples provide a complete description of the structure and use of exemplary embodiments. Although certain embodiments have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the scope of this invention. As such, the various illustrative embodiments of the present devices are not intended to be limited to the particular forms disclosed. Rather, they include all modifications and alternatives falling within the scope of the claims, and embodiments other than the one shown may include some or all of the features of the depicted embodiment. For example, penetrator 18 and/or channel 34 can have any suitable cross-sectional shape (e.g., triangular, square, rectangular, and/or the like) that permits the present apparatuses and methods to function as described in this disclosure. For example, components may be combined as a unitary structure, and/or connections may be substituted. Further, where appropriate, aspects of any of the examples described above may be combined with aspects of any of the other examples described to form further examples having comparable or different properties and addressing the same or different problems. Similarly, it will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments.

The claims are not intended to include, and should not be interpreted to include, means-plus- or step-plus-function limitations, unless such a limitation is explicitly recited in a given claim using the phrase(s) “means for” or “step for,” respectively. 

The invention claimed is:
 1. An apparatus comprising: a cannula having a first end, a second end, and a channel extending between the first end and the second end, the cannula having a primary portion and a distal portion between the primary portion and the second end, the distal portion configured such that a second end of the channel is disposed at an angle relative to a first end of the channel; a penetrator having an enlarged head and a monolithic wire extending from the enlarged head to a pointed distal end, a first transverse dimension of less than 1.2 millimeters (mm), and a second transverse dimension that is larger than the first transverse dimension, the penetrator including a primary portion extending from the enlarged head toward the distal end, and a penetration portion extending from the primary portion to the distal end, where the first transverse dimension is in the penetration portion and the second transverse dimension is in the primary portion, the penetrator configured to be disposed in the channel of the cannula such that the penetrator is movable between a retracted position and an extended position in which the distal end extends beyond the second end of the cannula by a penetration distance of at least 5 mm that is limited by the enlarged head contacting the cannula; where the penetrator is configured to be moved from the retracted position to the extended position substantially without rotation of the penetrator to form in subchondral bone a microfracture having a depth of at least 5 mm.
 2. The apparatus of claim 1, where the distal portion of the cannula is angled relative to the primary portion of the cannula.
 3. The apparatus of claim 1, where the enlarged head is unitary with the wire.
 4. The apparatus of claim 1, where a third transverse dimension is disposed at a point between the first transverse dimension and the primary portion; and the third transverse dimension is smaller than the first transverse dimension.
 5. The apparatus of claim 4, where the penetration portion has a length, and the third transverse dimension is substantially constant along part of the length of the penetration portion.
 6. The apparatus of claim 5, where the first transverse dimension is closer to the distal end than to the primary portion.
 7. The apparatus of claim 1, where the cannula includes a handle, and the apparatus further comprises: a penetrator removal tab including an opening with at least one transverse dimension that is smaller than a transverse dimension of the enlarged head of the penetrator, the penetrator removal tab configured to be disposed between the handle and the enlarged head with the penetrator extending through the opening and into the channel of the cannula such that a portion of the penetrator removal tab can be pressed toward the second end of the cannula to retract the penetrator relative to the cannula.
 8. The apparatus of claim 7, where the enlarged head includes a flange, and the at least one transverse dimension of the opening in the penetrator removal tab is smaller than a transverse dimension of the flange.
 9. The apparatus of claim 1, where a portion of the penetrator that extends beyond the second end of the cannula in the extended position has a substantially constant cross-section along a majority of its length.
 10. An apparatus comprising: a cannula having a first end, a second end, and a channel extending between the first end and the second end; a penetrator including a primary portion extending from a proximal end toward a distal end, a penetration portion comprising a monolithic wire extending from the primary portion to the distal end, where a first transverse dimension is in the penetration portion and a second transverse dimension is in the primary portion and the first transverse dimension is less than 1.2 millimeters (mm), the penetrator configured to be disposed in the channel of the cannula such that the penetrator is movable between a retracted position and an extended position in which the distal end extends beyond the second end of the cannula by a penetration distance of at least 5 mm; where the penetrator is configured to be moved from the retracted position to the extended position substantially without rotation of the penetrator to form in subchondral bone a microfracture having a depth of at least 5 mm; where the cannula includes a recessed portion and a shelf, the recessed portion extending from the first end of the cannula toward the second end of the cannula, the shelf disposed between the recessed portion and the second end of the cannula such that the penetration distance is limited by the enlarged head contacting the shelf; and where the enlarged head has a cylindrical shape with a longitudinal length and a transverse dimension that is smaller than the length.
 11. The apparatus of claim 10, where the recessed portion has a depth that is at least as large as the penetration distance.
 12. The apparatus of claim 10, where the enlarged head has a transverse dimension that is at least 90% of a corresponding transverse dimension of the recessed portion.
 13. An apparatus comprising: a cannula having a first end, a second end, and a channel extending between the first end and the second end; a penetrator having a primary portion and a penetration portion comprising a monolithic wire extending from the primary portion to a distal end, the penetration portion having a first transverse dimension of less than 1.2 millimeters (mm) and the primary portion having a second transverse dimension that is larger than the first transverse dimension, the penetrator configured to be disposed in the channel of the cannula such that the penetrator is movable between a retracted position and an extended position in which the distal end extends beyond the second end of the cannula by a penetration distance of at least 5 mm; where the penetrator is configured to be moved from the retracted position to the extended position substantially without rotation of the penetrator to form in subchondral bone a microfracture having a depth of at least 5 mm; where a coating is disposed on at least the penetration portion of the penetrator; and where the coating is hydrophilic.
 14. The apparatus of claim 13, where the coating comprises silver ions.
 15. An apparatus comprising: a cannula having a first end, a second end, and a channel extending between the first end and the second end; a penetrator having a primary portion and a penetration portion comprising a monolithic wire extending from the primary portion to a distal end, the penetration portion having a first transverse dimension of less than 1.2 millimeters (mm), the penetrator configured to be disposed in the channel of the cannula such that the penetrator is movable between a retracted position and an extended position in which the distal end extends beyond the second end of the cannula by a penetration distance of at least 5 mm; where the penetrator is configured to be moved from the retracted position to the extended position substantially without rotation of the penetrator to form in subchondral bone a microfracture having a depth of at least 5 mm; where the penetration portion is disposed between the primary portion and the distal end and a second transverse dimension is between the first transverse dimension and the primary portion; and where the second transverse dimension is smaller than the first transverse dimension.
 16. The apparatus of claim 15, where the penetration portion has a length, and the second transverse dimension is substantially constant along part of the length of the penetration portion.
 17. The apparatus of claim 16, where the first transverse dimension is closer to the distal end than to the primary portion.
 18. The apparatus of claim 17, where the penetrator has a first cross-sectional area at the first transverse dimension, the penetrator has a second cross-sectional area at the second transverse dimension, and the first cross-sectional area is larger than the second cross-sectional area.
 19. The apparatus of claim 18, where the penetrator has a first circular cross section at the first transverse dimension, and the penetrator has a second circular cross section at the second transverse dimension.
 20. An apparatus comprising: a cannula having a first end, a second end, and a channel extending between the first end and the second end; a penetrator having a primary portion and a penetration portion comprising a monolithic wire extending from the primary portion to a distal end, the penetration portion having a first transverse dimension of less than 1.2 millimeters (mm) and the primary portion having a second transverse dimension that is larger than the first transverse dimension, the penetrator configured to be disposed in the channel of the cannula such that the penetrator is movable between a retracted position and an extended position in which the distal end extends beyond the second end of the cannula by a penetration distance of at least 5 mm; a penetrator removal tab coupled to the penetrator and configured to retract the penetrator relative to the cannula; where the penetrator is configured to be moved from the retracted position to the extended position substantially without rotation of the penetrator to form in subchondral bone a microfracture having a depth of at least 5 mm; where: the cannula includes a handle, the penetrator includes a flange, the penetrator removal tab includes an opening that is has at least one transverse dimension that is smaller than a transverse dimension of the flange, and the penetrator removal tab is configured to be disposed between the handle and the flange with the penetrator extending through the opening.
 21. The apparatus of claim 20, where the penetrator removal tab includes a protrusion configured to extend toward the second end of the cannula and contact the handle to act as a fulcrum for pivoting the penetrator removal tab.
 22. The apparatus of claim 20, where the penetrator removal tab includes a protrusion configured to extend toward the second end of the cannula and contact the handle to act as a fulcrum for pivoting the penetrator removal tab. 